Modifying effects of 2,4-D and Glyphosate exposures on gut-liver-adipose tissue axis of diet-induced non-alcoholic fatty liver disease in mice
Guilherme Ribeiro Romualdo, Letícia Cardoso Valente, Jéssica Luri Hisano de Souza, Josias Rodrigues, Luı́s Fernando Barbisan
Abstract
Nonalcoholic fatty liver disease (NAFLD), which is linked to western diet (WD) intake, affects 30% of the world's population and involves the crosstalk of liver steatosis, hypertrophy/inflammation of adipose tissue and deregulation of gut microbiome. Glyphosate and 2,4-D are some of the most applied herbicides worldwide, and their roles in NAFLD have not been investigated. Thus, the present study evaluated whether glyphosate and 2,4-D, in single or mixed exposure, alter WD-induced NAFLD in a mouse model. Male C57Bl/6 mice (n = 10/group) received a fat (30% lard, 0.02% cholesterol), and sucrose-rich diet (20%) and high sugar solution (23.1 and 18.9 g/L of fructose and glucose) for 6 months. Simultaneously, animals received glyphosate (0.05 or 5 mg/kg/day), 2,4-D (0.02 or 2 mg/kg/day), or their combination (0.05 +0.02 or 5 +2 mg/kg/day) by intragastrical administration (5 ×/week). Doses were based on the Acceptable Daily Intake (ADIs) or No Observed Adverse Effect Level (NOAEL) levels. Herbicide exposures featured differential responses. WD-induced obesity, hypercholesterolemia, and hyperglycemia remained unaltered. Compared to the group receiving only WD, only the concomitant exposure to WD and 2,4-D (2 mg) enhanced the percentage of mice with moderate/severe hepatic inflammation, CD68 macrophage infiltration, and malondialdehyde levels in the liver. In line, this herbicide modulated immune response- (including Cd4, C8b, Cd28, Cxcr3, Cxcr6) and oxidative stress-related (such as Gsta1, Gsta2, Gsta4, Gstm1, Gstm2, Gstm3, Gstm4, Nqo1, Gpx2) genes in the hepatic transcriptome analysis. This exposure also enriched pro-inflammatory Deferribacteres phylum in fecal microbiome. In general, the herbicide mixtures did not feature the same effects attributed to 2,4-D isolated exposure. Our findings indicate that 2,4-D, at a dose within the toxicological limits, was able to induce disturbances in mainly at the liver and gut axes involved in NAFLD development in male mice.